Chicken Caecum Research Articles

Modulation of cytokine gene expression by selected Lactobacillus isolates in the ileum, caecal tonsils and spleen of Salmonella-challenged broilers

Probiotics have been used to control Salmonella colonization in the chicken intestine. Recently, we demonstrated that certain selected Lactobacillus isolates were able to reduce Salmonella infection in the chicken spleen and liver as well as down-regulated Salmonella pathogenicity island 1 virulence gene expression in the chicken caecum. To further understand the mechanisms through which Lactobacillus protected chickens from Salmonella infection, the present study has investigated the Lactobacillus isolate(s)-induced host immune response of chickens to Salmonella enterica serovar Typhimurium infection. A thorough examination of cytokine gene expression in the ileum, caecal tonsils, and spleen on days 1 and 3 post-Salmonella infection showed a dynamic spatial and temporal response to Salmonella infection and Lactobacillus treatments. In most instances, it was evident that treatment of chickens with Lactobacillus isolates could significantly attenuate Salmonella-induced changes in the gene expression profile. These included the genes encoding pro-inflammatory cytokines [lipopolysaccharide-induced TNF factor, interleukin (IL)-6, and IL-8], T helper 1 cytokines [IL-12 and interferon (IFN)-γ], and T helper 2 cytokines (IL-4 and IL-10). Another important observation from the present investigation was that the response induced by a combination of Lactobacillus isolates was generally more effective than that induced by a single Lactobacillus isolate. Our results show that administration of certain selected Lactobacillus isolates can effectively modulate Salmonella-induced cytokine gene expression, and thus help reduce Salmonella infection in chickens.

Bacteroides caecigallinarum sp. nov., isolated from caecum of an Indonesian chicken.

Three strains of anaerobic Gram-stain-negative, short to longer rod-shaped bacteria isolated from the caecum of chicken in Indonesia were studied using a polyphasic taxonomic approach. These strains belonged to the genus Bacteroides, based on sequence analysis of 16S rRNA and hsp60 (groEL) genes, with similarities of 93.2-94.1 and 89.8-90.8 %, respectively, to the closest recognized species, Bacteroides coprocola JCM 17929T. Sugar fermentation and enzyme characteristics, cellular fatty acid profiles, menaquinone profiles and metabolic end products were also investigated. Furthermore, DNA-DNA hybridization studies confirmed that the three novel strains are different from the closest related species. The strains were also found to be distinct from each other on the basis of ribotype profiles. The DNA G+C contents of the three strains were 41.1-41.8 mol%. Based on phenotypic and phylogenetic characteristics, a novel species, Bacteroides caecigallinarum sp. nov., is proposed (type strain C13EG111T = LIPI12-4-Ck773T = JSAT12-4-Ck773T = InaCC B455T = NBRC 110959T).

High quality draft genome sequence of Bacteroides barnesiae type strain BL2(T) (DSM 18169(T)) from chicken caecum.

Bacteroides barnesiae Lan et al. 2006 is a species of the genus Bacteroides, which belongs to the family Bacteroidaceae. Strain BL2T is of interest because it was isolated from the gut of a chicken and the growing awareness that the anaerobic microbiota of the caecum is of benefit for the host and may impact poultry farming. The 3,621,509 bp long genome with its 3,059 protein-coding and 97 RNA genes is a part of the Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes (KMG) project.

Identification of O-glycan Structures from Chicken Intestinal Mucins Provides Insight into Campylobactor jejuni Pathogenicity*

The Gram-negative bacteria Campylobactor jejuni is the primary bacteria responsible for food poisoning in industrialized countries, and acute diarrheal illness is a leading cause of mortality among children in developing countries. C. jejuni are commensal in chickens. They are particularly abundant in the caecal crypts, and poultry products are commonly infected as a result of cross-contamination during processing. The interactions between C. jejuni and chicken intestinal tissues as well as the pathogenic molecular mechanisms of colonization in humans are unknown, but identifying these factors could provide potential targets to reduce the incidence of campylobacteriosis. Recently, purified chicken intestinal mucin was shown to attenuate adherence and invasion of C. jejuni in the human colorectal adenocarcinoma cell line HCT-8 in vitro, and this effect was attributed to mucin O-glycosylation. Mucins from different regions of the chicken intestine inhibited C. jejuni binding and internalization differentially, with large intestine>small intestine>caecum. Here, we use LC-MS to perform a detailed structural analysis of O-glycans released from mucins purified from chicken large intestine, small intestine, and caecum. The O-glycans identified were abundantly sulfated compared with the human intestines, and sulfate moieties were present throughout the chicken intestinal tract. Interestingly, alpha 1-2 linked fucose residues, which have a high binding affinity to C. jejuni, were identified in the small and large intestines. Additionally, N-glycolylneuraminic/N-acetylneuraminic acid containing structures present as Sd(a)-like epitopes were identified in large intestine samples but not small intestine or caecum. O-glycan structural characterization of chicken intestinal mucins provides insights into adherence and invasion properties of C. jejuni, and may offer prospective candidate molecules aimed at reducing the incidence of infection.

Extensive characterization of Campylobacter jejuni chicken isolates to uncover genes involved in the ability to compete for gut colonization.

BackgroundCampylobacter jejuni is responsible for human foodborne enteritis. This bacterium is a remarkable colonizer of the chicken gut, with some strains outcompeting others for colonization. To better understand this phenomenon, the objective of this study was to extensively characterize the phenotypic performance of C. jejuni chicken strains and associate their gut colonizing ability with specific genes.ResultsC. jejuni isolates (n = 45) previously analyzed for the presence of chicken colonization associated genes were further characterized for phenotypic properties influencing colonization: autoagglutination and chemotaxis as well as adhesion to and invasion of primary chicken caecal cells. This allowed strains to be ranked according to their in vitro performance. After their in vitro capacity to outcompete was demonstrated in vivo, strains were then typed by comparative genomic fingerprinting (CGF). In vitro phenotypical properties displayed a linear variability among the tested strains. Strains possessing higher scores for phenotypical properties were able to outcompete others during chicken colonization trials. When the gene content of strains was compared, some were associated with different phenotypical scores and thus with different outcompeting capacities. Use of CGF profiles showed an extensive genetic variability among the studied strains and suggested that the outcompeting capacity is not predictable by CGF profile.ConclusionThis study revealed a wide array of phenotypes present in C. jejuni strains, even though they were all recovered from chicken caecum. Each strain was classified according to its in vitro competitive potential and its capacity to compete for chicken gut colonization was associated with specific genes. This study also exposed the disparity existing between genetic typing and phenotypical behavior of C. jejuni strains.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-015-0433-5) contains supplementary material, which is available to authorized users.

Associations between Campylobacter levels on chicken skin, underlying muscle, caecum and packaged fillets

A study was performed with the aim to investigate associations between Campylobacter in chicken caecum, carcass skin, underlying breast muscle and packaged breast fillets. Samples were taken from 285 chickens from 57 flocks and analysed according to ISO 10272. Campylobacter spp. were isolated from caecal samples from 41 flocks. From birds of the same 41 flocks Campylobacter could be detected and quantified in 194 (68%) skin samples. Moreover, Campylobacter spp. were enumerated in 13 (5%) underlying muscle samples originating from 9 of the 41 flocks. The mean number of Campylobacter spp. in the 194 skin samples which could be counted was 2.3 log cfu/g and for the 13 underlying muscle samples 1.3 log cfu/g. Campylobacter could only be quantified in those breast muscle samples with a finding in corresponding skin sample. Five packaged chicken fillets were taken from each 25 of the 57 flocks and analysed both quantitatively and qualitatively. In qualitative analysis Campylobacter was detected in 79 (63%) fillets from 16 flocks and quantified in 24 (19%) samples from 11 flocks.The results showed a significant association (P < 0.05) between findings of Campylobacter on carcass skin (log cfu/g) and the proportion of Campylobacter positive breast muscle samples.

Gene expression in the chicken caecum in response to infections with non-typhoid Salmonella.

Chickens can be infected with Salmonella enterica at any time during their life. However, infections within the first hours and days of their life are epidemiologically the most important, as newly hatched chickens are highly sensitive to Salmonella infection. Salmonella is initially recognized in the chicken caecum by TLR receptors and this recognition is followed by induction of chemokines, cytokines and many effector genes. This results in infiltration of heterophils, macrophages, B- and T-lymphocytes and changes in total gene expression in the caecal lamina propria. The highest induction in expression is observed for matrix metalloproteinase 7 (MMP7). Expression of this gene is increased in the chicken caecum over 4000 fold during the first 10 days after the infection of newly hatched chickens. Additional highly inducible genes in the caecum following S. Enteritidis infection include immune responsive gene 1 (IRG1), serum amyloid A (SAA), extracellular fatty acid binding protein (ExFABP), serine protease inhibitor (SERPINB10), trappin 6-like (TRAP6), calprotectin (MRP126), mitochondrial ES1 protein homolog (ES1), interferon-induced protein with tetratricopeptide repeats 5 (IFIT5), avidin (AVD) and transglutaminase 4 (TGM4). The induction of expression of these proteins exceeds a factor of 50. Similar induction rates are also observed for chemokines and cytokines such as IL1β, IL6, IL8, IL17, IL18, IL22, IFNγ, AH221 or iNOS. Once the infection is under control, which happens approx. 2 weeks after infection, expression of IgY and IgA increases to facilitate Salmonella elimination from the gut lumen. This review outlines the function of individual proteins expressed in chickens after infection with non-typhoid Salmonella serovars.

Effect of diclazuril on intestinal morphology and SIgA expression in chicken infected with Eimeria tenella.

Secretory immunoglobulin A (SIgA), as a vital actor involving in the mucosal immunity, plays a key role in defending a variety of pathogenic infections, such as bacteria, viruses and parasites. Eimeria tenella is an obligate intracellular apicomplexan parasite contacting with the digestive tract mucosa and specially parasitizes chicken caecum, causing a severe form of coccidiosis. Coccidiosis is currently mainly controlled using chemotherapeutic agents. Diclazuril, a classic coccidiostat, was used widely in the poultry industry. Because of the rising problem of drug resistance, it is therefore crucial to understand the pattern of the SIgA expression in the action of diclazuril against E. tenella. In this study, the intestinal morphology in the caecum was analyzed by haematoxylin-eosin (HE) staining, and the SIgA expression was examined by immunohistochemical technique. At the same time, the duodenum, jejunum and ileum tissues have also been evaluated. HE staining results showed that E. tenella infection caused severe damage characterized by structural disorder, haemorrhage, inflammatory cell infiltration, serous and fibrinous exudation in chicken caecum and invisible damage in the duodenum, jejunum and ileum. With the treatment of diclazuril, the damage in the caecum was alleviated obviously. Immunohistochemical analysis demonstrated that the SIgA level in the infected group was increased in the duodenum (p < 0.05), jejunum and ileum, respectively, but decreased (p < 0.01) in the caecum, compared with the control group. Interestingly, the SIgA level was decreased in the duodenum (p < 0.05), jejunum and ileum but increased (p < 0.05) in the caecum in the infected/diclazuril group in comparison to the infected group. The results showed that diclazuril effectively alleviated the damage in the caecum induced by E. tenella and provided a cure for coccidiosis by improving the immune function in chickens.

Fate of Salmonella Senftenberg in broiler chickens evaluated by challenge experiments

Experimental and epidemiological evidence has indicated the respiratory route to be a potential portal of entry for salmonellas in poultry. The purpose of this study was to evaluate and compare the infectivity of Salmonella enterica serovar Senftenberg following oral gavage, intratracheal or intravenous challenge in chickens. Seven-day-old chicks were challenged with either 104 or 106 colony-forming units of S. Senftenberg per chick by oral gavage, intratracheal or intravenous challenge, respectively, in two independent trials. Chickens were humanely killed 24 h post challenge and S. Senftenberg was cultured and enumerated from caecal contents, caecal tissue–caecal tonsils and liver and spleen. In both trials, intratracheal delivery of S. Senftenberg was the only route that allowed colonization of the caeca of chickens when compared with oral gavage or intravenous challenge in a dose response fashion (P < 0.05). Liver and spleen samples yielded no S. Seftenberg after the lower dose challenge by the oral or intratracheal route and only low levels following the high-dose administration by these routes, whereas intravenous challenge resulted in recovery of the organisms after both doses. The results of the present study suggest that S. Senftenberg entering the blood is likely to be cleared and will not be able to colonize caeca to the same extent as compared with intratracheal challenge. Clarification of the potential importance of the respiratory tract for transmission of salmonellas under field conditions may be of critical importance to develop intervention strategies to reduce the transmission in poultry.

Microbial and Carbohydrate Active Enzyme profile of buffalo rumen metagenome and their alteration in response to variation in the diet.

Rumen microbiome represents rich source of enzymes degrading complex plant polysaccharides. We describe here analysis of Carbohydrate Active Enzymes (CAZymes) from 3.5 gigabase sequences of metagenomic data from rumen samples of Mehsani buffaloes fed on different proportions of green or dry roughages to concentrate ration. A total of 2597 contigs encoding putative CAZymes were identified by CAZyme Analysis Toolkit (CAT). The phylogenetic analysis of these contigs by MG-RAST revealed predominance of Bacteroidetes, followed by Firmicutes, Proteobacteria, and Actinobacteria phyla. Moreover, a higher abundance of oligosaccharide degrading and debranching enzymes in buffalo rumen metagenome and that of cellulases and hemicellulases in termite hindgut was observed when we compared glycoside hydrolase (GH) profile of buffalo rumen metagenome with cow rumen, termite hindgut and chicken caecum metagenome. Further, comparison of microbial profile of green or dry roughage fed animals showed significantly higher abundance (p-value<0.05) of various polysaccharide degrading bacterial genera like Fibrobacter, Prevotella, Bacteroides, Clostridium and Ruminococcus in green roughage fed animals. In addition, we found a significantly higher abundance (p-value<0.05) of enzymes associated with pectin digestion such as pectin lyase (PL) 1, PL10 and GH28 in green roughage fed animals. Our study outlines CAZyme profile of buffalo rumen metagenome and provides a scope to study the role of abundant enzyme families (oligosaccharide degrading and debranching enzymes) in digestion of coarse feed.

Identification of Key Genes in the Response toSalmonella enterica Enteritidis,Salmonella enterica Pullorum, and Poly(I:C) in Chicken Spleen and Caecum

Salmonella enterica Enteritidis (S. Enteritidis) and Salmonella enterica Pullorum (S. pullorum) are regarded as a threat to poultry production. This study's aim is to characterize the expression profiles in response to three different challenges and to identify infection-related genes in the chicken spleen and caecum. Groups of the Chinese chicken breed Langshan were challenged with either S. Enteritidis, S. pullorum, or poly(I:C). The concentrations of cytokines and antibodies and the Salmonella colonization level of the caecum and liver were detected in each group at 7 days postinfection. Expression microarray experiments were conducted using mRNA isolated from both spleen and caecum. Crucial differentially expressed genes (DEGs) associated with immunity were identified. Four DEGs were identified in spleen of all three challenge groups (RBM16, FAH, SOX5, and RBM9) and different four genes in caecum (SOUL, FCN2, ANLN, and ACSL1). Expression profiles were clearly different among the three challenged groups. Genes enriched in the spleen of birds infected with S. pullorum were enriched in lymphocyte proliferation related pathways, but the enriched genes in the caecum of the same group were primarily enriched in innate immunity or antibacterial responses. The DEGs that appear across all three challenge groups might represent global response factors for different pathogens.

Early immune gene expression responses to Salmonella enteritidis infection in indigenous chickens

Salmonella enteritidis (SE) is a common cause of food-borne disease in humans and loss of growth in poultry. An effective method to inhibit salmonellosis is to increase the genetic resistance of poultry to Salmonella through genetic selection programmes that may be performed using phenotypic or genotypic data. A better understanding of the effects of Salmonella infection on the expression of inflammatory and anti-infectious cytokines and antimicrobial molecules is essential for choosing potential markers in selection programmes. The aim of this study was to investigate the expression of NRAMP1, TLR4, IL8 and IFNg genes in the caecum and spleen of Malaysian village chickens and red jungle fowl 48 h after inoculation with SE. Real-time reverse transcription PCR was used to quantify the fold-change in mRNA expression. The results showed that all the genes were highly expressed 48 h post-infection in the caecum of the village chickens. Overall, these results showed that Malaysian indigenous chickens have appropriate innate immune responses to SE infection.

Isolation of coagulase negative Enterococcous sp. strains from non-broiler chicken producing bacteriocin active against Staphylococcus aureus

Abstract Lactic acid bacteria (LAB) were isolated from the bile, gizzard, intestine and caecum of the Malaysian domestic non-broiler chicken. Of the 56 isolates grown on MRS agar plates, 7 - namely, B3L3, B4L4, G5L5, B5L6, B10L7, I1L8, and C4L10 - showed inhibition against the methicillin resistant Staphylococcus aureus (MRSA). These isolates were all Gram positive cocci, non-spore forming, and catalase negative. The purified fraction from the three phase partitioning (TPP) method, employing t-butanol and ammonium sulfate, produced inhibitory zones of 8 to 18 mm in diameter on the indicator organism, Staphylococcus aureus (MRSA). The TPP purified fraction contained heat stable proteins of about 10 kDa in size and was inactivated by trypsin. Based on the partial rDNA sequences (&gt;89% similarity), isolates B4L4 and G5L5 belonged to Enterococcus hirae; isolate B3L3 belonged to Enterococcus faecium; isolates B5L6, B10L7, I1L8 to Enterococcus faecalis; and isolate C4L10 to Enterococcus mundtii. These probiotic strains, exclusively isolated from the Malaysian non-broiler chicken, produced an antimicrobial protein or bacteriocin which was active against a pathogenic strain of methicillin resistant Staphylococcus aureus (MRSA).

Development of a HPLC–UV method for the quantitative determination of four short-chain fatty acids and lactic acid produced by intestinal bacteria during in vitro fermentation

A rapid and sensitive HPLC–UV method for the quantitative determination of four short-chain fatty acids (SCFAs) and lactic acid (LA) produced during in vitro fermentation is presented.Extraction of SCFAs from supernatants of bacterial cultures is aggravated due to their polarity and volatility. Detection can only be performed at a short, non-selective UV wavelength (210nm), due to the lack of any significant chromophore. Therefore special attention was paid to the optimization of the sample preparation procedure and the HPLC–UV conditions. The final extraction procedure consisted of a liquid–liquid back extraction using diethylether. Prior to HPLC–UV analysis the samples were acidified (pH<2) in order to improve retention of the SCFA's and LA on the Hypersil Gold aQ column.Matrix-matched calibration graphs were prepared for all analytes of interest (range 0.5–50mM) and correlation and goodness-of-fit coefficients were between 0.9951–0.9993 and 3.88–8.27%, respectively. Limits of detection and quantification ranged from 0.13 to 0.33mM and 0.5 to 1.0mM, respectively. The results for the within-day and between-day precision and accuracy fell within the ranges specified.The reported validated method has been successfully used for the in vitro screening of supernatants of bacterial cultures for the presence of butyric acid, aiming to select for butyric acid-producing bacteria. In addition, the method has been used to determine the production pattern of selected fatty acids by bacterial species isolated from human feces and chicken caeca.

Screening for lactic acid bacteria capable of inhibiting Campylobacter jejuni in in vitro simulations of the broiler chicken caecal environment

Thermotolerant Campylobacter spp., specifically Campylobacter jejuni and Campylobacter coli, are the most common bacterial causes of human gastroenteritis in developed countries. Consumption of improperly prepared poultry products and cross contamination are among the main causes of human campylobacteriosis. The aim of this study was to identify lactic acid bacterial (LAB) strains capable of inhibiting C. jejuni growth in initial in vitro trials ('spot-on-lawn' method), as well as in batch fermentation studies mimicking the broiler caecal environment. These experiments served as an indication for using these strains to decrease the capability of Campylobacter to colonise and grow in the chicken caeca during primary production, with the aim of reducing the number of human campylobacteriosis cases. A total of 1,150 LAB strains were screened for anti-Campylobacter activity. Six strains were selected: members of the species Lactobacillus reuteri, Lactobacillus agilis, Lactobacillus helveticus, Lactobacillus salivarius, Enterococcus faecalis and Enterococcus faecium. After treatment with catalase, proteinase K and a-chymotrypsin, anti-Campylobacter activity of cell-free culture supernatant fluid (CSF) for all six strains was retained, which indicated that activity was probably not exerted by bacteriocin production. Based on the activity found in CSF, the compounds produced by the selected strains are secreted and do not require presence of live bacterial producer cells for activity. During initial in vitro fermentation experiments, the E. faecalis strain exhibited the highest inhibitory activity for C. jejuni and was selected for further fermentation experiments. In these experiments we tested for therapeutic or protective effects of the E. faecalis strain against C. jejuni MB 4185 infection under simulated broiler caecal growth conditions. The best inhibition results were obtained when E. faecalis was inoculated before the C. jejuni strain, lowering C. jejuni counts at least one log compared to a positive control. This effect was already observed 6 h after C. jejuni inoculation.

The effects of polymorphisms in IL-2, IFN-γ, TGF-β2, IgL, TLR-4, MD-2, and iNOS genes on resistance to Salmonella Enteritidis in indigenous chickens

Salmonella Enteritidis is a major cause of food poisoning worldwide, and poultry products are the main source of S. Enteritidis contamination for humans. Among the numerous strategies for disease control, improving genetic resistance to S. Enteritidis has been the most effective approach. We investigated the association between S. Enteritidis burden in the caecum, spleen, and liver of young indigenous chickens and seven candidate genes, selected on the basis of their critical roles in immunological functions. The genes included those encoding interleukin 2 (IL-2), interferon-γ (IFN-γ), transforming growth factor β2 (TGF-β2), immunoglobulin light chain (IgL), toll-like receptor 4 (TLR-4), myeloid differentiation protein 2 (MD-2), and inducible nitric oxide synthase (iNOS). Two Malaysian indigenous chicken breeds were used as sustainable genetic sources of alleles that are resistant to salmonellosis. The polymerase chain reaction restriction fragment-length polymorphism technique was used to genotype the candidate genes. Three different genotypes were observed in all of the candidate genes, except for MD-2. All of the candidate genes showed the Hardy–Weinberg equilibrium for the two populations. The IL-2-MnlI polymorphism was associated with S. Enteritidis burden in the caecum and spleen. The TGF-β2-RsaI, TLR-4-Sau 96I, and iNOS-AluI polymorphisms were associated with the caecum S. Enteritidis load. The other candidate genes were not associated with S. Enteritidis load in any organ. The results indicate that the IL-2, TGF-β2, TLR-4, and iNOS genes are potential candidates for use in selection programmes for increasing genetic resistance against S. Enteritidis in Malaysian indigenous chickens.

Synchronous development of Eimeria tenella in chicken caeca and utility of laser microdissection for purification of single stage schizont RNA

Eimeria tenella is recognized worldwide as a significant pathogen in the poultry industry. However, a lack of methods for isolating developing schizonts has hindered the use of transcriptome analyses to discover novel and developmentally regulated genes. In the present study, we characterized the long-term successive development of E. tenella in infected chicken caeca and assessed the utility of laser microdissection (LMD) for the isolation of schizont RNA. Developmental stages, including those of the first, second, and third-generation schizonts and gametocytes, were synchronous. Using LMD, only the mature second-generation schizonts were successfully excised from the lamina propria, and non-degraded RNA was purified from the schizonts. E. tenella-specific genes were amplified by reverse transcription polymerase chain reaction (RT-PCR). These results augment our understanding of the E. tenella life cycle, and reveal LMD as a potentially useful tool for gene expression analyses of the intracellular stages of E. tenella.

English

The sensititivity of thermophilic&nbsp;Campylobacter&nbsp;strains isolated from caecum of broiler chickens as well as caecum and colon of pigs and human stools, were tested against erythromycin. In 16 strains isolated in broiler chickens, resistance rate was found to be 12.50%. Three of 10 strains of&nbsp;Campylobacter&nbsp;jejuni&nbsp;and one of 6 strains ofCampylobacter&nbsp;coli&nbsp;isolated from broiler chickens were resistant to erythromycin. In 15 strains of thermophilic&nbsp;Campylobacters&nbsp;isolated from pigs, resistance rate to erythromycin was 40.00%. Resistance was exhibited more often in&nbsp;C. coli&nbsp;(50.00%) as compared to&nbsp;C. jejuni&nbsp;(20.00%). In 24 strains isolated from humans, resistance was demonstrated at the rate of 12.50%. Out of 17 strains of&nbsp;C. jejuni&nbsp;isolated from humans, resistance was exhibited in 17.65% strains. None of 7 strains of&nbsp;C. coliisolated from humans exhibited resistance to erythromycin. ThermophilicCampylobacters, especially&nbsp;C. coli&nbsp;isolated from pigs were more resistant to erythromycin than strains isolated from humans and broiler chickens. Therefore, a great attention should be directed to the macrolides monitoring in swine farming in order to prevent resistance in animals and its subsequent spread to human. &nbsp; Key words:&nbsp;Campylobacter&nbsp;spp., resistance, erythromycin.

Butyrate production in phylogenetically diverse Firmicutes isolated from the chicken caecum

SummarySixteen butyrate‐producing bacteria were isolated from the caecal content of chickens and analysed phylogenetically. They did not represent a coherent phylogenetic group, but were allied to four different lineages in the Firmicutes phylum. Fourteen strains appeared to represent novel species, based on a level of ≤ 98.5% 16S rRNA gene sequence similarity towards their nearest validly named neighbours. The highest butyrate concentrations were produced by the strains belonging to clostridial clusters IV and XIVa, clusters which are predominant in the chicken caecal microbiota. In only one of the 16 strains tested, the butyrate kinase operon could be amplified, while the butyryl‐CoA : acetate CoA‐transferase gene was detected in eight strains belonging to clostridial clusters IV, XIVa and XIVb. None of the clostridial cluster XVI isolates carried this gene based on degenerate PCR analyses. However, another CoA‐transferase gene more similar to propionate CoA‐transferase was detected in the majority of the clostridial cluster XVI isolates. Since this gene is located directly downstream of the remaining butyrate pathway genes in several human cluster XVI bacteria, it may be involved in butyrate formation in these bacteria. The present study indicates that butyrate producers related to cluster XVI may play a more important role in the chicken gut than in the human gut.

Study on Two Inoculation Routs of Salmonella enteritidis in Abilities to Colonize in Internal Organs and to Contaminate of Eggs in Broiler Breeder Hens

Two groups of chickens were inoculated orally and intravenously with 10 and 10 CFU S. 10 6 enteritidis organisms consequently. Heavier infection of liver spleen, caecum, small intestines, infundibulumovules and cloac-vagina of chickens that inoculated orally were observed. In intravenously inoculated group high infection of liver-spleen and cloacvagina were noticed. In oral group egg production were more decreased and fecal shedding was higher than intravenously group.